Researchers at the University of Pittsburgh School of Medicine have developed a mouse model of major depressive disorder (MDD) that is based on a rare genetic mutation that appears to cause MDD in the majority of people who inherit it. The findings, which were published online on May 19, 2011, in the American Journal of Medical Genetics Part B: Neuropsychiatric Genetics EarlyView, could help to clarify the brain events that lead to MDD, and contribute to the development of new and better means of treatment and prevention. This report also illustrates an advance in the design of recombinant mouse models that should be applicable to many human diseases. "Major depressive disorder is a leading cause of suffering, disability, and premature death from all causes including suicide. While the cause currently is unknown, twin and adoption studies indicate that genetic factors account for 40 to 70 percent of the risk for developing this common disorder," explained lead author Dr. George Zubenko, professor of psychiatry, Pitt School of Medicine. "In this report, we describe how we constructed a laboratory mouse strain that mimics the brain mechanism that leads to major depression in humans, rather than symptoms," he said. "Nonetheless, in our initial characterization, the mutant mice exhibited several features that were reminiscent of the human disorder, including alterations of brain anatomy, gene expression, behavior, as well as increased infant mortality. These findings support the role of the genetic variant in the development of MDD, and affirm the mutant mouse strain as a model of MDD worthy of further study," Dr. Zubenko said. Hugh B. Hughes, III, M.S., served as the co-author of this report.

Universitat Autònoma de Barcelona researchers have discovered that Viagra® drastically reduces multiple sclerosis symptoms in animal models with the disease. The research, published in Acta Neuropathologica, demonstrates that a practically complete recovery occurs in 50% of the animals after eight days of treatment. Researchers are confident that clinical trials soon will be carried out in patients given that the drug is well tolerated and has been used to treat sexual dysfunction in some multiple sclerosis patients. Multiple sclerosis is the most common chronic inflammatory disease of the central nervous system and one of the main causes of disability among young adults. The disease is caused by the presence of multiple focuses of demyelination (loss of myelin sheaths around the axons, affecting the ability of neurons to communicate) and neurodegeneration in different areas of the central nervous system. There is currently no cure for the disease, although some drugs have proven effective in fighting symptoms and preventing it from progressing. A research team from the UAB Institute of Biotechnology and Biomedicine directed by Dr. Agustina García, in collaboration with the research team directed by Dr. Juan Hidalgo from the UAB Institute of Neurosciences, has studied the effects of a treatment using sildenafil, sold as Viagra®, in an animal model of multiple sclerosis known as experimental autoimmune encephalomyelitis (EAE). Researchers demonstrated that a daily treatment with sildenafil after disease onset quickly reduced clinical signs, with a practically complete recovery in 50% of the cases after eight days of treatment.